Oxygen-deuterium complex

Paleotemperatures derived from noble gas analyses are potentially more meaningful than those from oxygen-deuterium analyses because the noble gas content is a direct measure of the temperature of the water at the time of infiltration rather than a complex function of geographic and meteorological factors as is the case with 2H and 180. Despite this potential superiority, few noble gas studies of water paleotemperatures have been published. Specifically, questions need to be answered relative... 

Fig. 25. Series of towers comprising part of the heavy water production plant at Ontario Hydro s Bruce nuclear power complex near Tiverton on the shores of Lake Huron. Heavy water is a clear, colorless liquid that looks and tastes like ordinary water. It occurs naturally in ordinary water in the proportion of approximately one part heavy water to 7000 parts of ordinary water. While ordinary water is a combination of hydrogen and oxygen (H20), heavy water (D.-1.0) is made of up of deuterium—a form, or isotope, of hydrogen—and oxygen. Deuterium is heavier than hydrogen in that it has an extra neutron in its atomic nucleus, so heavy water weighs about 10% more than ordinary water. It also has different freezing and boiling points. It is the extra neutron that makes heavy water more suitable than ordinary water for use in CANDU nuclear reactors as both a moderator and a heat transport medium. (Ontario Hydro, Toronto, Ontario, Canada)...

Ratio of stable isotopes may be measured in a mass spectrometer it is advisable to use relatively simple molecules (for example from degradation of one under study) so that the parent peaks are isolated from other possible ones. For example COj and C02 have parent masses at 44 and 45 and the only nearby peaks are those from small amounts of O and 0 in the oxygen. A complex organic molecule will normally yield many smaller peaks immediately around the parent due to normal deuterium, C and 0 and determination of isotopic enrichments is only possible in uncomplicated mass spectra. Results good to 0.1-0.2% are easily obtained but simultaneous collection of ions from the two peaks of interest using a dual collector instrument gives precision to 0.01%. 

As we will see, some anomalies in the isotopic composition of carbon, hydrogen and oxygen can be explained on the basis of this assumption, and we will start the discussion with the deuterium-rich matter in carbonaceous chondrites. This deuterium-rich matter is essentially present as complex macromolecules 70 73 96 97). The carbon in these samples is essentially normal 76,98). For some polymer-type fractions, the deuterium content is up to 32 times higher than the galactic value (D/H 2 x 10s in the number of atoms per cubic centimeter). High deuterium enrichments are known in interstellar molecules and the mechanism of this enrichment is fully understood. For an excellent review dealing with interstellar chemistry, see the paper by Winnewisser 99) and the previously mentioned book by Duley and Williams 13). 

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